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RFC 1213 - 6.8. The TCP Group

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### 6.8. The TCP Group

              -- the TCP group

              -- Implementation of the TCP group is mandatory for all
              -- systems that implement the TCP.

              -- Note that instances of object types that represent
              -- information about a particular TCP connection are
              -- transient; they persist only as long as the connection
              -- in question.

              tcpRtoAlgorithm OBJECT-TYPE
                  SYNTAX  INTEGER {
                              other(1),    -- none of the following

                              constant(2), -- a constant rto
                              rsre(3),     -- MIL-STD-1778, Appendix B
                              vanj(4)      -- Van Jacobson's algorithm [10]
                          }
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The algorithm used to determine the timeout value
                          used for retransmitting unacknowledged octets."
                  ::= { tcp 1 }

              tcpRtoMin OBJECT-TYPE
                  SYNTAX  INTEGER
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The minimum value permitted by a TCP
                          implementation for the retransmission timeout,
                          measured in milliseconds.  More refined semantics
                          for objects of this type depend upon the algorithm
                          used to determine the retransmission timeout.  In
                          particular, when the timeout algorithm is rsre(3),
                          an object of this type has the semantics of the
                          LBOUND quantity described in RFC 793."
                  ::= { tcp 2 }

              tcpRtoMax OBJECT-TYPE
                  SYNTAX  INTEGER
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The maximum value permitted by a TCP
                          implementation for the retransmission timeout,
                          measured in milliseconds.  More refined semantics
                          for objects of this type depend upon the algorithm
                          used to determine the retransmission timeout.  In
                          particular, when the timeout algorithm is rsre(3),
                          an object of this type has the semantics of the
                          UBOUND quantity described in RFC 793."
                  ::= { tcp 3 }

              tcpMaxConn OBJECT-TYPE
                  SYNTAX  INTEGER
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The limit on the total number of TCP connections
                          the entity can support.  In entities where the
                          maximum number of connections is dynamic, this
                          object should contain the value -1."
                  ::= { tcp 4 }

              tcpActiveOpens OBJECT-TYPE
                  SYNTAX  Counter
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The number of times TCP connections have made a
                          direct transition to the SYN-SENT state from the
                          CLOSED state."
                  ::= { tcp 5 }

              tcpPassiveOpens OBJECT-TYPE
                  SYNTAX  Counter
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The number of times TCP connections have made a
                          direct transition to the SYN-RCVD state from the
                          LISTEN state."
                  ::= { tcp 6 }
              tcpAttemptFails OBJECT-TYPE
                  SYNTAX  Counter
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The number of times TCP connections have made a
                          direct transition to the CLOSED state from either
                          the SYN-SENT state or the SYN-RCVD state, plus the
                          number of times TCP connections have made a direct
                          transition to the LISTEN state from the SYN-RCVD
                          state."
                  ::= { tcp 7 }

              tcpEstabResets OBJECT-TYPE
                  SYNTAX  Counter
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The number of times TCP connections have made a
                          direct transition to the CLOSED state from either
                          the ESTABLISHED state or the CLOSE-WAIT state."
                  ::= { tcp 8 }

              tcpCurrEstab OBJECT-TYPE
                  SYNTAX  Gauge
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The number of TCP connections for which the
                          current state is either ESTABLISHED or CLOSE-
                          WAIT."
                  ::= { tcp 9 }

              tcpInSegs OBJECT-TYPE
                  SYNTAX  Counter
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The total number of segments received, including
                          those received in error.  This count includes
                          segments received on currently established
                          connections."
                  ::= { tcp 10 }

              tcpOutSegs OBJECT-TYPE
                  SYNTAX  Counter
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The total number of segments sent, including
                          those on current connections but excluding those
                          containing only retransmitted octets."
                  ::= { tcp 11 }

              tcpRetransSegs OBJECT-TYPE
                  SYNTAX  Counter
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The total number of segments retransmitted - that
                          is, the number of TCP segments transmitted
                          containing one or more previously transmitted
                          octets."
                  ::= { tcp 12 }

              -- the TCP Connection table

              -- The TCP connection table contains information about this
              -- entity's existing TCP connections.

              tcpConnTable OBJECT-TYPE
                  SYNTAX  SEQUENCE OF TcpConnEntry
                  ACCESS  not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                          "A table containing TCP connection-specific
                          information."
                  ::= { tcp 13 }

              tcpConnEntry OBJECT-TYPE
                  SYNTAX  TcpConnEntry
                  ACCESS  not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                          "Information about a particular current TCP
                          connection.  An object of this type is transient,
                          in that it ceases to exist when (or soon after)
                          the connection makes the transition to the CLOSED
                          state."
                  INDEX   { tcpConnLocalAddress,
                            tcpConnLocalPort,
                            tcpConnRemAddress,
                            tcpConnRemPort }
                  ::= { tcpConnTable 1 }

              TcpConnEntry ::=
                  SEQUENCE {
                      tcpConnState
                          INTEGER,
                      tcpConnLocalAddress
                          IpAddress,
                      tcpConnLocalPort
                          INTEGER (0..65535),
                      tcpConnRemAddress
                          IpAddress,
                      tcpConnRemPort
                          INTEGER (0..65535)
                  }

              tcpConnState OBJECT-TYPE
                  SYNTAX  INTEGER {
                              closed(1),
                              listen(2),
                              synSent(3),
                              synReceived(4),
                              established(5),
                              finWait1(6),
                              finWait2(7),
                              closeWait(8),
                              lastAck(9),
                              closing(10),
                              timeWait(11),
                              deleteTCB(12)
                          }
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The state of this TCP connection.

                          The only value which may be set by a management
                          station is deleteTCB(12).  Accordingly, it is
                          appropriate for an agent to return a `badValue'
                          response if a management station attempts to set
                          this object to any other value.

                          If a management station sets this object to the
                          value deleteTCB(12), then this has the effect of
                          deleting the TCB (as defined in RFC 793) of the
                          corresponding connection on the managed node,
                          resulting in immediate termination of the
                          connection.

                          As an implementation-specific option, a RST
                          segment may be sent from the managed node to the
                          other TCP endpoint (note however that RST segments
                          are not sent reliably)."
                  ::= { tcpConnEntry 1 }

              tcpConnLocalAddress OBJECT-TYPE
                  SYNTAX  IpAddress
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The local IP address for this TCP connection.  In
                          the case of a connection in the listen state which
                          is willing to accept connections for any IP
                          interface associated with the node, the value
                          0.0.0.0 is used."
                  ::= { tcpConnEntry 2 }

              tcpConnLocalPort OBJECT-TYPE
                  SYNTAX  INTEGER (0..65535)
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The local port number for this TCP connection."
                  ::= { tcpConnEntry 3 }

              tcpConnRemAddress OBJECT-TYPE
                  SYNTAX  IpAddress
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The remote IP address for this TCP connection."
                  ::= { tcpConnEntry 4 }

              tcpConnRemPort OBJECT-TYPE
                  SYNTAX  INTEGER (0..65535)
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The remote port number for this TCP connection."
                  ::= { tcpConnEntry 5 }

              -- additional TCP objects

              tcpInErrs OBJECT-TYPE
                  SYNTAX  Counter
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The total number of segments received in error
                          (e.g., bad TCP checksums)."
                  ::= { tcp 14 }

              tcpOutRsts OBJECT-TYPE
                  SYNTAX  Counter
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The number of TCP segments sent containing the
                          RST flag."
                  ::= { tcp 15 }

Next: 6.9. The UDP Group

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RFC 1213 - 6.8. The TCP Group